Electromagnetic impacting medium forming (EIMF): a new method forming process for magnesium alloy sheet

A new forming process for magnesium alloy sheet, namely, electromagnetic impacting medium forming (EIMF), is proposed. Medium is compressed by strong magnetic force which is produced from varied magnetic field between coil and driver sheet. Magnesium alloy sheet can be deformed by a strong force from medium. In EIMF, once impacting or more times impacting is easily implemented, that is difficulty in conventional electromagnetic forming. Effects of different discharge energy and temperature were investigated. Peak forming heights increased linearly with increasing discharge energy and temperature. Distribution of contour and thickness had been revealed. Strains could be improved by increasing temperature and discharge energy. Twice impacting process was carried out. The forming height was enhanced obviously in contrast with results obtained at once impacting. Fracture morphology and optical microstructure were analyzed. It is found that brittle fracture at room temperature and ductile fracture at 200 °C appeared. Due to high strain rate forming process, deformation mechanism (non-basal slip systems) has limit effect. And at 200 °C, twinning is also a main mechanism for AZ31 sheet deformation in EIMF. In further work, EIMF for formability of AZ31 sheet will be improved by affected the deformation mechanism.